1. Field of the Invention
The present invention relates generally to cordless telephone systems. In particular, the invention relates to a cordless telephone system capable of modular expansion of its features and capabilities through the addition of wireless peripherals.
2. Background Art
Cordless telephone devices have become increasingly popular among individuals both at home and in the workplace. Modern cordless telephones offer a wide range of features. While conventional cordless telephones provide a base unit which communicates with a single cordless telephone handset, many modern systems provide for expansion in the number of handsets that may be utilized with a cordless telephone base unit.
The heart of typical existing cordless telephone systems is the cordless telephone base unit. The base unit typically determines which features are provided by the cordless telephone system. Features typically dictated by the base unit include the number of telephone lines to which the system can be connected, the number of handsets that can be used, and whether ISDN telephone lines can be accessed. Some base units which have recently been discussed further include an interface to a cellular telephone. Such a base unit is described in Published U.S. Application No. 20020072390A1, assigned to Meridian Concepts L.L.C. If a user desires features that are not provided by the user's current base unit, the user typically must replace the entire cordless telephone system to upgrade to a system having the desired features.
Outside the realm of consumer cordless telephones, expandable telephone systems are known in the private branch exchange (“PBX”) art. Typically such systems include a main PBX unit having a plurality of physical slots which can be optionally populated by additional line interface circuit boards to increase the capacity of the system. However, the increased size of the primary base unit caused by provision of physical expansion slots may be highly undesirable in some applications. Furthermore, extra cost is incurred by providing the connectors and other hardware required to support the electrical interfaces to potential expansion units. When expansion devices are added to such a system, they typically must be collocated with the main base unit and sometimes require expert technicians to reprogram and/or configure the modified system, limiting the flexibility of the system configuration and potentially incurring extra costs in routing multiple communications lines to the single main unit location and technical support.